Hi Teng,
If our plugin is free from 3rd party dependencies and you, at the end,
find it very useful; U would be more than happy to add it to the xrootd
repo for such use cases.Let me know.
Andy
On Fri, 2 Mar 2018, Teng Li wrote:
> Hi Fabrizio,
>
> I've been working on XCache integration of ATLAS and had the same problem as
> you do. The xrootd client plugin provides a fast solution of using different
> urls for reading/writing.
>
> https://github.com/feipengsy/XrdCLROProxyPlugin
>
> After installing the client-side plugin above (and configuring
> /etc/xrootd/client.plugins.d/ProxyRW-plugin.conf), the url of reading
> activity will be prefixed with the XCache server address while the url of
> writing stays unchanged. That's currently I'm doing tests with. Hope it could
> help.
>
> Cheers,
> Teng
>
>
> Quoting Fabrizio Furano <[log in to unmask]> on Fri, 2 Mar 2018 10:29:59 +0100:
>
>> Hi Andy,
>>
>> thanks for the hints. My opinion is that a passthrough option would be
>> a very big plus for the caching proxy, and I was sincerely surprised
>> by this limitation.
>>
>> For some of our use cases I believe that we will start using it without
>> caching, as I can't imagine how to give a transparent service by having
>> to force clients to use different paths for reading and writing.
>>
>> What do you think ?
>>
>> Thank you
>> Fabrizio
>>
>> On 03/01/2018 06:09 PM, Andrew Hanushevsky wrote:
>>> Correct, we don't support a writable cache because that's not what a cache
>>> is all about. Does the origin support writes? If so,
>>> we could potentially provide a cache passthrough option. Otherwise, if the
>>> readable and writable path differ, he could have run
>>> two proxies -- one caching for read access and a passthru proxy for
>>> writing then setup a redirect directive in the primary proxy
>>> (i.e. the one that will be initially used) to direct writes to the
>>> passthru proxy based on path.
>>>
>>> Andy
>>>
>>> On Thu, 1 Mar 2018, Fabrizio Furano wrote:
>>>
>>>> Hi,
>>>>
>>>> Mihai is trying to setup a small Pss machine that also works as a cache.
>>>>
>>>> For reading it seems to work fine, yet it stubbornly refuses to write
>>>> files with
>>>> this error:
>>>>
>>>>> 180301 17:27:38 13788 XrdFileCache_Manager: debug Cache::Attach()
>>>>> root:[log in to unmask]:1094//eos/xdc/testing/hello.txt?&oss.asize=14&oss.lcl=1
>>>>> location: <deferred open>
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_fstat:
>>>>> fn=/eos/xdc/testing/hello.txt
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdResponse: 0100
>>>>> sending 46 data bytes; status=0
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100
>>>>> req=write dlen=14
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100
>>>>> fh=0 write 14@0
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_write: 14@0
>>>>> fn=/eos/xdc/testing/hello.txt
>>>>> 180301 17:27:38 13788 ofs_write: root.3008:20@xdc-test-fst1 Unable to
>>>>> write /eos/xdc/testing/hello.txt; operation not supported
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100
>>>>> discarding 0 bytes
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdResponse: 0100
>>>>> sending err 3005: Unable to write
>>>>> /eos/xdc/testing/hello.txt; operation not supported
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 XrootdProtocol: 0100
>>>>> req=close dlen=0
>>>>> 180301 17:27:38 13788 root.3008:20@xdc-test-fst1 ofs_close: use=1
>>>>> fn=/eos/xdc/testing/hello.txt
>>>>
>>>> If we remove the directive pss.cachelib then writes work instead.
>>>>
>>>> Can anyone give us a clue please ?
>>>>
>>>> Thank you
>>>> Fabrizio and Mihai
>>>>
>>>>
>>>
>>
>>
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>
>
>
> ----------------------------------------------------------------------
> Teng LI, PDRA
> School of Physics and Astronomy, University of Edinburgh
>
> Email: [log in to unmask]
> Telephone: +44 (0) 742 2910721
>
> Room 5412, James Clerk Maxwell Building,
> Kings Buildings, Peter Guthrie Tait Road
> Edinburgh EH9 3FD, United Kingdom
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>
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> Scotland, with registration number SC005336.
>
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